Mechanical seal

Abstract

A high sealability mechanical seal which has a small-volume mating ring, which highly efficiently transmits the shaft's revolving force to the mating ring, and which has a minimal load variation on the sliding face. The gist of the present invention is in a mechanical seal where the bellows is made of rubber; a coiled wave spring which is a spirally wound narrow thin strip is interposed in a compressed state between the end of the seal ring side of the bellows and a middle wall of the roughly U-shaped cross-sectional cartridge; and the other end of the bellows is mounted, on the inner circumferential side of the coiled wave spring, via a driving band in the inner circumferential casing of said roughly U-shaped cross-sectional cartridge.

What is claimed is: 
     
       1. A mechanical seal comprising an inner circumferential casing which is secured to a shaft of a drive mechanism and rotates with the shaft and an outer circumferential casing which is secured to a housing of said drive mechanism, said inner circumferential casing having a mating ring mounted as a sliding member which rotates with the shaft, with inner circumferential and back sides of the mating ring being press fit into an end of a sleeve via a cup gasket; and said outer circumferential casing having mounted therein a seal ring that slides against the mating ring and an adjacent bellows for biasing the seal ring in an axial direction, which are fitted into a roughly U-shaped cross-sectional cartridge, wherein the bellows is made of rubber, a coiled wave spring, said coiled wave spring being a spirally wound narrow thin strip, is interposed in a compressed state between a seal ring side end of the bellows and a middle wall of the roughly U-shaped cross-sectional cartridge, and the other end of the bellows is mounted on an inner circumferential side of the coiled wave spring via a driving band in an inner-circumferential casing of the roughly U-shaped cross-sectional cartridge.